Petroleum distillate compositions containing fatty oil pitches



Patented Sept. 24, 1957 PETROLEUM DISTILLATE COIVIPOSITIONS CON- TAWINGFATTY OIL PITCHES Charles T. Brown and Robert L. Dinsmore, Long Beach,and Wendell F. Deeter, Bellflower, Calif., assignors to Richfield OilCorporation, 'a corporation of Delaware No Drawing. Application February4, 1954, Serial No. 408,287.

5 Claims. (Cl. 44-61) This invention relates to liquid petroleumhydrocarbons having added thereto small but effective amounts ofcorrosion inhibiting substances which are residues from refining. V

It is well known in the art that rusting or corrosion may occur on steelor iron surfaces in contact with hydrocarbons and water. All types ofliquid hydrocarbon products including gasoline, kerosene, thinners,stove oil, diesel oil and residual fuel oil, exhibit this corrosiveeffect. Corrosion of ferrous metals by le'aded gasoline is particularlysevere. Water is almost always present in association with hydrocarbonsin storage, blending and distribution systems. Water is frequentlyintroduced into petroleum systems with the hydrocarbon itself either inthe dissolved or suspended state, and in addition may be intentionallyintroduced as a bottom seal for a storage tank. The Water may even beformed in situ by condensation from the air in a tank due to changes inatmospheric conditions. Further it is common practice to use water as afollower for a particular petroleum stock in a pipe line, to cleanand'flushlines and tanks with Water and to use water in the oil tanks ofships as ballast orfor cleaning purposes.

It is obvious that rusting at any point in the manufacturing,distribution or terminal system represents a considerable monetary lossdue toextra expense for cleaning Under severe conditions of "corrosion,it may even be necessary to replace the expensive equipment.

and repair of these systems.

Furthermore, rust formed in one part of a fuel system is frequentlytransported with the fuel to other parts. The rust may plug screens andfilters, re-

sulting in inefiicient operation or in some cases, complete stoppage.Rust in these systems is particularly detrimental Where parts aremachined to close tolerances, due to excessive wear caused by theforeign material.

In recent years, in addition to the corrosion problems mentioned above,a new source of greater difliculty has arisen in connection with the useof hydrocarbon solvents for various chemicals which tend to acceleratecorrosion.

Thisproblem has been particularly troublesome in the case ofDDT-hydrocarbon solvent systems. Another corrosion problem has arisen inthe wood treating industry "where it is customary to use a petroleumsolvent for pentachlorophenol. This solution is often subjected to awide range of temperatures, from atmospheric to 250 F. and

to pressures ranging from :15" of mercury vacuum to 150 lbs. per squareinch gauge. Further, the presence of water, steam and air is usual.Under these conditions, abnormal corrosion may occur due to the presenceof the chlorinated compound andthe wide variation in operatingconditions. Corrosion in these systems tends to shorten greatly theuseful life of the equipment.

In the present-invention, liquid petroleum hydrocarbon systems areinhibited against corrosion by having added --thereto a rust orcorrosion inhibitor which is afatty acid pitch which is the residue fromthe-refining of a fatty oil, e. g., of animal, vegetable-or fish origin;The pitches which are useful are soluble in the liquid petroleumhydrocarbon at least to an extent suificient to afford the desiredinhibiting effect. Mixtures of these pitches are also effective toinhibit rust and corrosion. The fatty acid pitches employed in ourinvention are in general, viscous, high-boiling substances which arevariously described in the art as residues, foots, still-bottoms, breakmaterials, acidulated dewatered soapstocks and pitches.

These pitches are commercially available materials which are produced inconventional fatty oil refining operations. For instance, acidulateddewatered soapstocks are derived from the fatty oil through alkalirefining of the oil e. g., see U. S. Patents Nos. 2,100,274 to2,100,277. The other refining methods affording the desired pitches areacid refining, steam refining or distillation, desliming and degummingmethods including hydration and heat treatment and liquid-liquidextraction procedures. All of these methods are well known operations,many of which are described in U. S. Patents, e. g., see Nos. 2,150,732and 2,201,063. Still-bottoms residues useful in this invention may alsobe obtained by the splitting of glycerides. Glycerides in raw fatty oilsare split with acid-type catalysts and the valuable products removed byvacuum distillation at elevated temperatures. The mixed vegetable oilpitch referred to in Table I below was obtained as a bottoms product inthe splitting and vacuum distillation of mixed soya and cottonseed oils.

The vegetable pitches useful in this invention can be obtained asby-products in the processing of cottonseed, flaxseed, soya bean, tung,coconut and other oils of vegetable origin. The marine pitches employedare those obtained as by-products in the processing of Whale oil,menhaden oil, cod oil, fish liver oils of any kind and other oils offish or marine origin. The animal pitches utilized are derived asby-products in the refining of fats and other materials of animalorigin. It is the residues from the processing or distillation of thesefatty oils, irrespective of their source, which are useful in thisinvention.

The fatty oil pitches useful in this invention are difficult to definechemically due to differences in source and changes which occur duringprocessing. They can generally be characterized as a mixture ofglycerides, unsaponifiables, fatty acids and esters. The pitch may bepolymerized to varying degrees depending on processing conditions, i.e., a mixed vegetable and animal pitch may contain approximately 35%glycerides and polymerized material, 25% unsaponifiables and 40% fattyacids and esters. Table I below indicates the approximate compositionand boiling range of several pitches which are useful in this invention.The pitches were distilled under vacuum and the values for thedistillation temperatures corrected to atmospheric pressure.

The effectiveness of .the fatty oil pitches appears to be due to thefact that these materials preferentially wet metal surfaces, forming athin, perhaps monomolecular film thereon which is protective against theattack of corrosive materials in contact with the surfaces. Thepitchesuseful in this invention are effective inhibitors for petroleum productssuch as gasoline, naphthas, thinners, kerosene,

2,so7,527 v i stove oil, diesel oil, lube oils and residual fuel oil,and are TA I useful in any type of manufacturing, distribution or con-Rating: 7 t Percent rust sumer fuel system. Our inhibitors areparticularly use- A e None. fulvin systemshandling light distillates.By. light .dis- B++ Trace.

rtillates we mean petroleum distillates of a viscosity not B+ Less than5.

exceeding that of gas oil. The inhibitingrnaterials are B 5-25.inexpensive since they are, for the most part, ,by-products. C 50.

, Thepropertiesof the pitches may vary widely without D .4 50-75-afiecting their value as corrosion inhibitors. Also, pitches i E 7 .fromdiiferent sources are effective either singly or as a 10 Th effect ofpitch concentration on the rust rating of 1 mixture. The table belowlistsaselection of pitches which a leaded ethyl gasoline is shown in thetable below.

i are among those elfective for the purpose of this inven- The pitchused was a mixed animal-vegetable pitch having tion. a saponificationnumber of 180; a

Table II Properties of typical pitches 1 Sp. gr. at Acid num- Sap. num-Viscosity, Pitch source Type 60 F. ber ber S. S. U. V., ,7 p at210F.;.

Cottonseed 1.01 38 103 2, 000. s .97 37 139 403 .92 87 183 52.2 1.00 99161 701 Fish 93 109 197 46. 7 Vegetable and animal 982 9. 4 180 r 118Fish and .97 39 144 456 (S. S. U. V. seconds Saybolt Universalviscosity.)

For the purposeof this invention, the pitch can be TABLE IV used in theform derived from the fatty oil refining prop cedures, or can be dilutedwith a solvent, or blended with g i v ibSJM bbls" Rust S other materialsfor facility in handling. For example, a B+ mixed pitch of vegetable andanimal origin having a Say- 7 3 V bolt Universal viscosity at 210 F. of11.8 seconds may 40 5 I B++ be diluted with 2 parts by volume ofStoddard solvent to one part of pitch, thus reducing the viscosity to 87seconds 1, Saybolt Universal at 60 F. These pitches prevent cor- Theeffestlveness of QOTTOSlOB lnhlbltors 0f l l rosion by forming a film onthe metal surface to be pro- P 9 not PP i 50111126 0f the vl'esldlleStected thus preventing contact'with water, dilute acids pltqhes used-T1115 faclf 1S lllusfl'ated y b below and other reactive materials. Thepitches are petroleum shows the f I'atmg Obtamed b 115mg P 9 fromoil-soluble and can be diluted with any appropriate solvent l l-l P- 111a leaded gasoline at a concentration such as petroleum thinners,aromatics or alcohols. V of D 1000 e The effective concentrations offatty oil pitches for in- V I B' E V hibition of corrosion are generallyvery low. This fact .p t rating is advantageous because in theconcentrations used the e 'materials do not affect the other propertiesor specifica- Fish e tlons of the product. In generaleffectlveconcentrations 7, Vegetable (com'mseed) v of pitch range fromas httle as 1, lb. per 1000 barrels of vegetable (soya) the liquidpetroleum hydrocarbon to be treated to as much Animal (Ebony fat: as 5percent by we1ght. Mostof the pltches are dark in Animal (Ebony fat #40)v color WhlCh limits their use 1n light drstillates such as Mix dvegetable & animal 1(140 Sap. No.) B++ gasoline to 1 lb. to 15 lbs. per1000 barrels. In lube 0118, Mixed vegetable & animal (180 San B however,the product color is not so lmportant and con- Mixed fish andcbentratrlons iot p tch as high as 5 percent by welght can 0 yegetable'u oil) B eemoe. a

The f llowing specific examples of the use ofthe intests f also been 1w? q m t the hibiting materials of our invention in various petroleum if s' plt-ch as FOUOSwnJPmbHOIFH leaded products will serve to illustratethe invention. The rust gasohn? cgncentrailon', mixed: ammalwegfiratings referred to in the tables were determined by a tablepltchhavmg'a sagomficanon number of modification of ASTM method n-sss-szrwhich is as the resultshwn Table Q A follows: Gasoline (350 ml.)containing inhibitor is poured TABLE V1 .into a 4-00 ml. beaker, aolished steel rod is inserted V V f r f and'the gasoline stirred foraperiod of 30minutes. At M bbls: 1 Rust mung the end of that time, 50ml. of hydrocarbon is withdrawn 1 g I f Y E and 30 ml. of water added.Stirring is continued for 3 /2 2V V C hours. At the end of the 3 /2 hourperiod, the steel rod .2 i B is removed and the percentage of rustedsurface is esti- 1 I I B+ mated. The testis conducted at roomtemperature in The static test is run using a piece of ASTM grade thepresence of air andthe ratings; are madeas follows: p

1010 steel, 1%" x 5" x 1%",which has been sanded to remove all traces ofrust and corrosion and then degreased by washing with benzene andacetone, followed by heating at 230-250 F. for thirty minutes. The stripis placed in a 6-02. bottle containing 150 ml. of the product to betested and shaken for 30 minutes. Fifteen m1. of distilled water isadded and shaking continued for 10 minutes more. The bottle is placed inaninclined position to prevent the end of the steel strip from remainingin direct contact with the main body of water. Before placing in theinclined position, the bottle is generally shaken to suspend water andleave droplets on the top surface of the strip. The bottle is leftundisturbed for 24 hours, then is gently shaken and turned over with theother side of the metal strip facing upwards. After another 24 hours,the steel strip is rated according to the scale employed for themodified ASTM method D-665- 521 tests.

The pitches of this invention in addition to being effective corrosioninhibitors are also stabilizing agents for tetraethyl lead in gasolineagainst the action of sunlight. It is common knowledge that commercialgasoline now on the market containing tetraethyl lead becomes cloudywhen exposed to direct sunlight, due to the decomposition of the leadcompound. When modern gasoline pumps are used, the decomposition oftetraethyl lead is not par ticularly troublesome because the gasoline isnot exposed to direct sunlight. This is not true, however, in old stylegasoline pumps which frequently have a l-gallon glass bowl which isexposed to sunlight. When gasoline is allowed to stand for any length oftime in the old style pumps, a cloudy precipitate is likely to form. Thestabilizing elfect of our inhibiting pitches has been shown by exposingsamples of leaded gasoline with and without the inhibitor in clear glassbottles to direct sunlight. The gasoline tested contained approximately2 cc. of tetraethyl lead per gallon. It was noted that the firstdecomposition of lead in the uninhibited sample occurred after 3% hours,the initial decomposition of lead compound in the sample inhibited witha vegetable-animal pitch in a concentration equivalent to 2 lbs. ofpitch per 1000 barrels was 13 /2 hours. Still bottoms from thedistillation of soya beam oil and cottonseed oil were found to exhibitsimilar properties of stabilization for tetraethyl lead in gasoline.

A further example of the results obtained by the corrosion inhibitor ofthis invention is as follows: The test consisted of incorporating amixed vegetable oil pitch at a concentration of 5 lbs. per 1000 barrelsin a stove oil with a neat rust rating of E. The rust rating of theinhibited sample was B++.

An example of the efiectiveness as corrosion inhibitors of the pitchesof this invention when used in jet fuel is illustrated by the resultsshown in Table VII.

TABLE VII Concentra- Rust Pitch tion,L lb./ rating M bbls.

The pitches of this invention are also effective as corrosion inhibitorsin lube products at concentrations as low as 01% to as much as 5% byweight. Tests made with a western refined turbine oil gave the resultsshown in Table IX below. The ratings in Table IX were determined by ASTMmethod D665-52T, which is a tentative method for determining the'rust-preventingcharacteristics of steam turbine oil in the presence ofwater. The procedure is the same as the modified method de scribed abovefor testing gasoline, except that the sample is run in a controlledtemperature bath at 140 F. for a period of 24 hours after the additionof water. A passing rating requires that there be no visible rust spotson a steel test specimen.

TABLE IX Concentra- Pitch source Type tion, wt. Rust rating percent 0.2Passes 0.5 Do. 0.2 Do. 0.2 Do. 0.5 Do.

Certain pitches due to their dark color may not in certain instances besuitable for use at the required concentrations in certain products.There are, however, other pitches such as tall oil pitch which are lightenough in color to be useful at the required concentrations in thesespecial products.

It has been found that concentrations as low as .0l% by weight of thecorrosion inhibitors of this invention frequently provide as much as 98%corrosion protection when added to special solvents used as carriers forother chemicals; however, it is occasionally necessary to useconcentrations as high as 1% of corrosion inhibitor for satisfactoryresults. As a specific example of this application of our invention, asmall quantity of inhibitor was added to 200 cc. of a petroleumhydrocarbon solvent containing 5% by weight of pentachlorophenol. Thismixture was transferred to an oxygen stability tube and 2% water added.A polished steel strip 1" x 10" and a block of fir, /2" x x 3" were theninserted into the tube. The tube was placed in the bomb of aconventional oxygen stability apparatus and kept under 100 lbs. ofoxygen pressure at a temperature of 212 F. for three hours. The bomb wasthen depressured and the tube removed and allowed to stand for 16 hours.The steel strip was inspected for rusting and the results reported Inpractice, the additives of this invention are usually present in suchsmall amounts that their presence is difficult to detect in petroleumproducts. It has been iqundthatq llt siqn pr t on fl y the a t v ofthisinvention is due, not only to one, but to many q mriqn nts, o h itchrwAramp e o i d m vegetable pitch, saponification No. 180, wasvextrac-tedwith acetone 'and both the extract and the rafiinate phases;

tested in a sample: of leaded gasoline having a neat rust rating of;E.""B0th phases" of the pitch gave a rating of B++ .when used at aconcentration of two lbs. per" l000'bbls.of gasoline. p We claim: 1 1 Acomposition consisting essentially of a lightpetroleum distillate havingincorporated therein a soluble fatty oil pitch in an amount effective asa corrosion inhibitor, said amount being-from 1 to 15 pounds perthousand barrels of said distillate.

2. The composltlonof claim 1 wherein said distillate is gasoline.

' .1 3. Thecomposition of claim 1 wherein said distillate is I a leadedgasoline.

4.; A composition consisting essentiallyl of light incorporatedthereinfa 'soluble fatty oil pitch in anamount efiectiveto inhibitcorrosion. and to lead, barrels of said distillate.

stabilize jtetraethyl sjc fhe file of this patent I UNITED sTAT s PAT TS2,014,235 Lowry Sept. 10, 1935" 2,339,796 'Musher ..L Jan. 25,19442,596,065 Brabets ;;.l lMay'6, 1952 2,668,138 Walker et a1.Feb.'-2,:1954. 2,671,761 Kalinowski et al Mar. 9,1954

2338-2347, December 1948.

lgtoj '15 pounds, per thousand barrels-c said amount beinglfrorn 1 to15pounds perthousand White et a1. Aug/17,1954? J 7 OTHER REFERENCES 5Industrialand Engineering Chemistry, v01. 4() pages

1. A COMPOSITION CONSISTING ESSENTIALLY OF A LIGHT PETROLEUM DISTILLATEHAVING INCORPORATED THEREIN A SOLUBLE FATTY OIL PITCH IN AN AMOUNTEFFECTIVE AS A CORROSION INHIBITOR, SAID AMOUNT BEING FROM 1 TO 15POUNDS PER THOUSAND BARRELS OF SAID DISTILLATE.